What happens when the unstoppable force meets the immovable object? We found out at Milan last week when two forces of nature collided. One was the annual Salone del Mobile, the Milan furniture fair – the biggest event in the design calendar, which sees hundreds of thousands of visitors descend on the city to buy and sell furniture, devour the latest trends and (above all) schmooze. The other was the cloud of volcanic ash sitting over northern Europe, a great fart in the face of the international jetset. It was unthinkable: here they were, the sunglasses-wearing, Campari-sipping design-world sophisticates, with their flying privileges withdrawn. Only one thing to do: panic.

The fair is the busiest week in Milan's year, when hotels can charge triple rates and still be turning people away. With rumours circulating that flights might not resume for several days, this was the wrong place to be stranded. And so La Dolce Vita became Escape from Milan. This many people haven't rushed for the Swiss border since the second world war. There were three-hour queues at the Stazione Centrale, with no promise of a ticket at the front – helpfully, the French railway was on strike. There were tales of people buying Fiat Cinquecentos to drive to London and then sell. There were 15-hour coach journeys back to Rotterdam. A bad accident would have wiped out the entire Dutch design scene.

In future years, no one will remember what the 2010 Milan furniture fair was like. So here are a few observations for posterity. One development this year was the emergence of a new design district in Lambrate. With the big business in Milan happening at the giant exhibition centre at Rho, the edgier fringe events cluster in pockets elsewhere in the city. The beauty of Milan is its seemingly endless supply of disused industrial buildings, where young designers can exhibit polished wood and delicate porcelain against raw concrete. In Lambrate, there were shows by venerable design schools such as the Royal College of Art and Design Academy Eindhoven alongside curated shows by up-and-coming designers from across Europe – particularly Holland, as Milan is the last outpost of Dutch colonialism. The work was all by designer-makers rather than manufacturers – a fact of life for the young designer – but there was a contagious energy here, a sense of like-minded people combining fresh ideas with impressive craftsmanship.

Do we really need any more chairs, people sometimes ask. This has always struck me as a silly question. We didn't need any more chairs when Gio Ponti created the featherweight Superleggera in 1955 or when Jasper Morrison designed the injection-moulded Air-Chair in 1999. But the chair is a cultural artefact, a constantly evolving embodiment of our collective psyche and technical prowess. You may as well ask, do we really need any more paintings? And yet design has this moral baggage that comes with the very notion of industrial-scale production. In the age of environmental anxiety, bad design is synonymous with pollution.

It's amazing how much pointless design you can see in Milan. It can sap the will of the most dedicated enthusiast. You see this in the vast exhibition halls at Rho, where thousands upon thousands of new chairs and sofas jostle for attention. One suspects that the Chilean architect Alejandro Aravena had these in mind when he designed his new chair for Vitra. Called Chairless, it is a simple woven strap that slips around your knees and back while you're sitting on the floor – a device used by the nomadic Ayoreo indians of Paraguay. Aravena sees it as the irreducible limit of what a chair can be, the moment when the noun "chair" becomes the verb "to sit". Others see it as a questionable gimmick. That may be, but as well as being the most affordable launch of the fair – at €19.99 – it was also the only one that paused to ask the question of what a chair is.

When the recession started to bite, there was a good deal of talk about how the design world would have to get creative to pull through. This year's fair proved that, in fact, the exact opposite happened. The industry contracted, limiting its output to the easy sells, to variations on a safe theme. Among these, there were nevertheless some desirable objects. Emeco's plastic variation of its Navy chair, made of recycled plastic Coke bottles, was one. Tom Dixon's Mesh chair for Magis was another. Outside of the fair itself, Martino Gamper was showing a seductively formed wooden chair for the British brand Established & Sons. But this was not a vintage year.

When I saw how many shows were by either septuagenarian or dead Italians, I realised there was clearly something afoot. In one of the most poetic shows, the wise old grump of Italian design, Enzo Mari, was exhibiting a beautiful series of found-object paperweights. At the Triennale Design Museum, the main exhibition was an interpretation of Italian design by Alessandro Mendini, who at 79 has just been invited back to edit Domus magazine for the second time. Elsewhere, the late, great Achille Castiglioni's miniature church models were on show. This is the curse of Italy: a gerontocracy so venerated that no one under the age of 60 gets a look-in. It has to be said that the shows by Mari and Mendini were my picks of 2010, but if we're going to talk about sustainable design culture, surely recycling the greybeards is a dead end.